Yeah I really don't buy it. They probably compiled a list of people they want to ban then just manually typed it in to ban people individually. It would explain the delay between some people's bans and others as well.

Thanks buddy.

It really could be anything. They probably banned you ages ago but you only now got the message. You could've been banned for posting or commenting in a completely unrelated subreddit. I know a lot of subs ban you if you comment in /r/kotakuinaction

You weren't banned for browsing their sub-reddits. One of their mods has told me that the ban messages were just delayed and you were banned a while ago. Not sure how that works though.